As mentioned in my previous log post I’ll be doing a big update soon (hopefully in the next week). I originally made 8 X-PCs, these have all been in use in the classroom for over a year and a half now. They have been used every school day and have had a lot of (ab)use from the students! I’m extremely pleased with how they have performed; they all still work and are all still in use.
There are a few things though that I wanted to change.
Firstly, the screen angle is a bit steep which can make it hard to see. I’ve seen some of the students prop up the front of the screen to angle it back a bit, which does work but I wanted a better solution.
Secondly, the living hinge is a bit prone to damage on the sides. The students tend to clip them with their bags as the walk past so some of them have taken a bit of damage.
Thirdly, some of the students like to yank the power cables out of the side, then leave them not quite plugged so the next user doesn’t quite know why they are not turning on.
Lastly and possibly most importantly, this design only works for one type of laptop. I have since been given loads more, so I wanted a way of making the design fit any type of laptop, so I can save them from being thrown away.
All of these issues meant a redesign of the whole project. I wasn’t too thrilled with this idea as it was originally designed in a 2D CAD package. I would’ve had to redesign every single part which is time consuming but also wouldn’t address the issue of making the design work with any type of laptop.
Just after finishing the original eight X-PCs I wanted to start work on a new 3D CAD project. At the time there was a lot of talk about FreeCAD https://www.freecadweb.org/ so I wanted to see what all the fuss was about. Conveniently, at the same time Hackspace Magazine were running a series of excellent tutorials, which I started to follow (These tutorials are now available as a book and free download https://hackspace.raspberrypi.com/books/freecad ). One of the tutorials was on parametric modelling, and this is as it turns out was exactly what I was looking for!
After getting stuck in with FreeCAD for the past year or so, I can now say It’s my favourite 3D CAD package. So I set about redesigning the X-PC as a FreeCAD parametric model. The design is now pretty much finished, with lots of changeable parameters. Most importantly you can change the screen height and width so the X-PC is now a universal design which will hopefully work with all sizes of laptop, which otherwise would’ve been destined for landfill. You can of course change the screen angle and I’ve also addressed the other issues – the PSU plug is now internal so it can’t be removed and the sides of the living hinge have been redesigned to make them more robust.
I have made a prototype of the new X-PC with the 2D file for laser cutting generated from the FreeCAD 3D model. I’m very pleased with how it has turned out and I’ll be posting some pictures over the next few days. I’ll also make a video of the parametric model so you can see the changes in action.